In the first part of the paper I reconstruct Kant’s proof of the existence of a ‘most real being’ while also highlighting the theory of modality that motivates Kant’s departure from Leibniz’s version of the proof. I go on to argue that it is precisely this departure that makes the being that falls out of the pre-critical proof look more like Spinoza’s extended natura naturans than an independent, personal creator-God. In the critical period, Kant seems to think that transcendental idealism allows him to avoid this conclusion, but in the last section of the paper I argue that there is still one important version of the Spinozistic threat that remains. -/- .